Blowpipe



BLOWPIPE W. J. JACOBSSON Filed Aug. 8, 1934 'll/ g/I/I/I/I/I/I/I Sept.20, 1938.

E AWIIII VI,

INVENTOR WILGOT I JACOBS 50 N ATTORNEY Patented Sept. 20, 1938 UNHTEDSTATES PATENT QFFEQE BLOWPIPE Application August 8,

11 Claims.

This invention relates to blowpipes and more particularly blowpipes inwhich fuel gas and a combustion supporting gas are mixed. The inventionrelates especially to such blowpipes in which a diluting gas is mixedwith one of the other gases before the final mixing.

One object of the invention is economy in the quantity of gas used.Another object is the provision of a construction to reduce the amountin popping or back flashing and which will insure safety to the operatorshould such popping occur. A further object is the provision of a simplerugged and inexpensive construction which will be capable of attainingthe desired results. Other objects will be apparent upon considerationof the present specification.

The invention is shown by way of illustration in the accompanyingdrawing in which:

Fig. 1 is a broken mid-section through a blowpipe constructed inaccordance with the invention;

Fig. 2 is a longitudinal mid-section taken on line 11-11 of Fig. l; and

Fig. 3 is a cross-section taken on line III-III of Fig. 1.

In the operation of blowpipes, economy of gas consumption frequentlybecomes an important factor. At times, therefore, the fuel gas, or thecombustion supporting gas, or both, have been diluted with another gas,for instance, atmospheric air. Under such conditions, however, thedanger of popping or flash backs is increased because the addition ofair makes possible the existence of a combustible mixture in the tubesand passages of the pipe to an extent which is not possible where suchtubes and passengers are full of a more concentrated gas which is mixed,adjacent the stem or even the tip of the blowpipe, with the other g'asnecessary for combustion. This is so because of the dilution of thecombustion-supporting gas with the nitrogen in the air. Such dilutioncauses the receding burning gas mixture, before burning out, to burnmore slowly and hence to travel farther into the blowpipe passages thanwould be the case with a more concentrated supply of oxygen. Greaterconcentration of oxygen would obviously cause quicker burning out of theflame by effecting more rapid combustion of the fuel gas. Speciallydesigned constructions are therefore desirable where such dilution takesplace.

A further consideration is the question of employing blowpipes underdifferent service condi:

55- tions and the desirability of changing the mix- 1934, Serial No.738,923

ture of fuel gas, combustion supporting gas and diluting gas to fittheservice requirement.

Referring now more particularly to the drawing there is shown a blowpipecomprising a handle I0, a stem ii and a coupling 52 joining the handleto the stem. An oxygen-supply conduit E3 extends longitudinally of thehandle it, and an acetylene-supply conduit Hi is disposed in similarposition within the handle parallel to the oxygen supply conduit. A ductl5 connects the oxygen-supply conduit with a chamber it in which anoxygen regulating valve E'l operates. The oxygen regulating valve isoperated by a valve stem l8 having a threaded portion is turning in acorresponding threaded portion of t e chamber It and controlled by aknurled head 20 at the outer end of the stern. A duct 2! connects thechamber it with the inlet side of an oxygen-air injector, which will nowbe described.

The forward part of the handle it has a cav ity 22 therein, and an airport 23 opens into the cavity 22 near its inner end. An oxygen-airinjector is formed by the cavity 22 and a nozzle 24 cooperatingtherewith. The nozzle 24 has a threaded section 25 thereon and isadapted to be screwed into corresponding threads in the cavity 22. Aplug 26, provided with a kerf 2l is adapted to be screwed into the endof the cavity 22, clearing the end of the plug by a considerabledistance and thereby forming an oxygen inlet chamber 28 in which theduct 2! terminates. A central bore 29 in the nozzle 24, communicatingwith the chamber 28, provides means for passage of the oxygen enteringthe chamber intoan aspirating chamber 353, formed between the threadedportion of the injector and the inner end of the cavity 22, into whichthe end of the nozzle 24 extends. The position of the air port 23 issuch that atmospheric air may freely enter the aspirating chamber 38. Apassage 3i coaxial with a bore 23 through the oxygen-air injector 24extends from the aspirating chamber 36 through the handle to one end ofa return bend conduit 32 which extends substantially the entire lengthof the handle. The other end of the return bend conduit terminates in achamber 33 at the base of a concave conical opening 3 in the forwardpart of the handle to which it delivers the oxygen-air ture which isprojected into it from the passage 3|.

A'duct 35 extends from the forward end of the acetylene conduit M to achamber 35, the en-- trance to which is controlled by an acetyleneregulating valve 31. The acetylene regulating rair through the air port23.

valve is carried by a stem 38 having a threaded section 39 thereonc0-acting with threads in the chamber 36 and operated by a knurled head46 at the end of the stem outside of the chamber. A duct 41 extends fromthe acetylene regulating chamber 36 to an annular groove 42 in the wallof the concave conical opening in the forward part of the handle I6.Thus, by turning the knurled head 46 in one direction the duct 35 isclosed and no acetylene may enter the chamber 36 from the acetyleneconduit l4, whereas by turning the knurled head 40 in the otherdirection the end of the duct 35 is opened and acetylene may flow intothe chamber 36 and out through the duct 4| and into the annular groove42 in the handle end.

Between the handle l0 and the stem I I a mixer 43 is disposed. As hereshown the mixer 43 is threaded into the rear end of the stem H and aconvex conical end mates with the concave conical opening in the forwardend of the handle. The mixer 43 has an axial passage 44 therethroughextending from the chamber 33 at the base of the concave conical opening34 in the forward end of the handle to an aspirating chamber 45 formedbetween the forward mixer end and the interior walls of the stem II. Theconvex conical end of the mixer 43 has an annular groove 46 thereinwhich registers with the annular groove 42 in the concave conical end ofthe handle, thus forming an annular chamber into which the acetyleneduct 4| extends. One or more longitudinal passages 41 extend from thegroove 46 through the mixer 43 substantially parallel to the axialpassage 44 therein and terminate in the aspirating chamber 45. An axialmixing throat 48 in the stem l I extends from the aspirating chamber 45to an expansion chamber 49 whence the mixture of gases passes throughthe stem to the tip of the blowpipe.

From the description already given the operation of the blowpipe will beobvious. When the knurled head 20 is turned so as to open the oxygenregulating valve l1, oxygen under greater pressure than the acetyleneflows into the receiving end of the oxygen-air injector. As the oxygenrushes through the bore 29 in the injector and into the aspiratingchamber it reduces the pressure in the aspirating chamber therebydrawing Passing into the passage 3| the oxygen draws air from theaspirating chamber with it and mixes with the air in the passage 3|before entering the return bend conduit 32. From the return bend conduit32 the oxygen-air mixture still under considerable pressure, enters thechamber 33 at the base of the concave conical opening in the forward endof the handle whence it passes through the axial passage 44 in the mixer43. The acetylene control valve 31 is opened by turning the knurled head40 and acetylene under lower pressure than the oxygen passes into theannular chamber 46 at the rear end of the mixer 44 whence it may flowthrough the longitudinal passages 41 into the aspirating chamber 45. Theoxygen-air mixture passing out of the end of the mixer 43 at highpressure tends to produce a vacuum in the aspirating chamber 45 andthereby assists the passage of acetylene to this chamber. Entering themixing throat 48 with considerable velocity the oxygen-air mixture drawswith it acetylene from the aspirating chamberand mixes with theacetylene in the mixing throat before passing into the expansion chamber49.

It will be noted that because the oxygen-air mixture is at all times ata higher pressure than the acetylene there will be no back-flow ofacetylene into the return bend conduit. Even if there should be suchback-flow and a tendency for combustion, the popping will beextinguished in the long passage provided by the return bend conduit.Furthermore, there will be no tendency for the oxygen-air mixture toflow backward toward the acetylene conduit through the passages 41because the shape of the mixer 43 insures that the travel of theoxygen-air mixture will be in the opposite direction.

In order to meet different requirements a series of substituteoxygen-air injecting nozzles may be used, the nozzles being adapted tomix different ratios of oxygen and air by having different sizes ofpassages therein and different nozzle diameters and lengths so as toincrease or decrease the size of the aspirating chamber 30. A substituteseries of oxygen-air fuel gas mixers may also be provided, the mixerpassages having dilferent diameters, or a different number of passagesbeing provided in the mixer, so that different relative quantities ofoxygen-air mixture and fuel gas may be passed through the mixer.

The example here described and shown in the drawing is presented merelyto indicate how the invention may be applied. Other forms of theinvention differing in detail but not in principle from that heredescribed will, of course, suggest themselves to those skilled in thisart.

I claim:

1. In a blowpipe, a handle; a stem extending from the forward end ofsaid handle to the discharge end of the blowpipe; an oxygen-air injectorin the forward part of said handle; means for supplying oxygen to saidinjector; and a return bend conduit connecting the discharge end of saidoxygen-air injector with said stem, said conduit extending substantiallythe entire length of said handle, said handle having a port therein foradmitting air to said injector.

2. In a blowpipe, a handle; an oxygen-air-fuel gas mixer. seated in theforward part of said handle; an oxygen-air injector in the forward partof said handle; means for supplying oxygen under pressure to saidinjector; means for admitting air to said injector; and a return bendconduit between the discharge end of said injector and said mixer, saidconduit extending substantially the entire length of said handle.

3. A blowpipe comprising a handle; an oxygen supply conduit and anacetylene supply conduit in said handle; an oxygen regulating valve, anacetylene regulating valve, and an oxygen-air injector all in theforward part of said handle; means for mixing and projecting gases atthe forward part of said handle, and a return bend conduit extendingfrom the discharge end of said oxygen-air injector to the intake side ofsaid mixing and projecting means; said handle having therein a ductconnecting said oxygen supply conduit with said oxygen regulating valve,a duct connecting said oxygen regulating valve with the oxygen inletside of said oxygen-air injector, a duct connecting said acetylenesupply conduit with said acetylene regulating valve, and a ductconnecting said acetylene regulating valve with said mixing andprojecting means.

4. A blowpipe comprising a handle; an oxygen supply conduit and anacetylene supply conduit in said handle; and an oxygen regulating valve,an acetylene regulating valve, and an oxygenair injector all in theforward part of said handle; means for mixing and projecting gases atthe forward part of said handle, and a return bend conduit extendingfrom the discharge end of said oxygen-air injector to the intake side ofsaid mixing and projecting means; said handle having therein a ductconnecting said oxygen supply conduit with said oxygen regulating valve,a duct connecting said oxygen regulating valve with the oxygen inletside of said oxygen-air injector, an air port connecting the oxygen exitside of said oxygen-air injector with the atmosphere, a duct connectingsaid acetylene supply conduit with said acetylene regulating valve, anda duct connecting said acetylene regulating valve with said mixing andprojecting means.

5. In a blowpipe, a handle; an oxygen-air injector in the forward partof said handle; an oxygen-air-acetylene mixer also in the forward partof said handle; means for supplying acetylene to said mixer; and meansfor supplying oxygen to the inlet side of said injector; said handlehaving in its forward part an air port connecting the oxygen exit sideof said oxygen-air injector with the atmosphere and a duct into whichsaid oxygen-air injector discharges, in combination with a return bendconduit connecting the duct into which said oxygen-air injectordischarges with said mixer, said conduit extending substantially theentire length of said handle.

6. In a blowpipe, a handle; an oxygen supply conduit and an acetylenesupply conduit in said handle; an oxygen regulating valve and an acetylene regulating valve in the forward part of said handle; an oxygen-airinjector also in the forward part of said handle; said handle havingtherein an air port connecting the oxygen exit side of said oxygen-airinjector with the atmosphere, a duct connecting said oxygen supplyconduit with said regulating valve, a duct connecting said oxygenregulating valve with the oxygen inlet side of said air injector, and aduct connecting said acetylene supply conduit with said acetyleneregulating valve; an oxygen-air-acetylene mixer adjacent the forwardpart of said handle; and a duct connecting said acetylene regulatingvalve with said mixer in combination with a return bend conduitconnecting the duct into which said oxygen-air injector discharges withsaid mixer, said conduit extending substantially the entire length ofsaid handle.

7. A blowpipe comprising a handle portion, a stem portion, and anoxygen-air-fuel gas mixer; said handle portion including an oxygenconduit, an acetylene conduit, an oxygen air conduit including at leastone sharp bend therein, the length of said oxygen-air conduit beingsubstantially in excess of the length of said handle portion, and anoxygen-air injector in said handle portion between said oxygen conduitand said oxygen-air conduit, said handle having a duct therein foradmitting air to said injector.

8. In a blowpipe, means for supplying a combustion supporting gas to amixer, said means comprising an oxygen-air injector adjacent the mixer,means for supplying oxygen under pressure to said injector, means foradmitting air to said injector, and a return bend conduit extending fromthe discharge end of said injector to the intake end of said mixer.

9. In a blowpipe, a handle having a cavity in the forward part thereofand a unitary return bend conduit connecting the interior of said cavitywith atmosphere, said conduit extending substantially the full length ofsaid handle; a mixing device located in said cavity and communicatingwith said return bend conduit; means for supplying said mixing devicewith fuel gas, said device having passage and tip dimensions adapted toproduce the properly proportioned mixture of fuel gas and air to meetthe requirements of the blowpipe for a given piece of work; and meansremovably securing said device in said cavity.

10. In a blowpipe, the combination of a handle portion and a stemportion; said handle portion including an oxygen conduit, an oxygen-airconduit, a fuel gas conduit, and a chamber between said oxygen conduitand said oxygen-air conduit, said chamber being threaded to receive aremovable injector nozzle, an injector nozzle within said chamber; saidhandle portion having a cavity at the forward end thereof adapted toreceive a rear portion of a second removable injector nozzle; said stemportion having a threaded cavity at the rear end thereof adapted toreceive a front portion of said second removable injector nozzle.

11. In a blowpipe, a handle of substantial length, a stem, an oxygen-airinjector at one end of the handle, an oxygen-air-fuel gas injector atthe same end of the handle, an oxygen conduit and a fuel gas conduitextending through said handle from the opposite end thereof andcommunicating respectively with said oxygenair injector and saidoxygen-air-fuel gas injector; and an oxygen-air conduit disposedintermediate said oxygen conduit and said fuel gas conduit, saidoxygen-air conduit being substantially twice the length of said oxygenconduit and said fuel gas conduit and communicating at each end with oneof said injectors.

WILGOT J. JACOBSSON.

